Exercise Induced Collapse (EIC) in Labrador Retrievers

Young, healthy Labrador retrievers sometimes suffer from a syndrome called Exercise Induced Collapse (EIC). It is associated with exercise intolerance and affected dogs can tolerate only mild or moderate exercise. These dogs normally collapse after 5 to 15 minutes of strenuous exercise, especially if the dog is overly excited or stressed. Symptoms include a wobbly gait and non-painful paralysis and the dog often losses control of its rear limbs. This is a newly characterized syndrome as veterinarians had previously thought it to be caused by malignant hyperthermia, hypoglycemia, electrolyte disturbances and cardiac rhythm disturbances to name just a few. The cause is however a genetic mutation. (Patterson et al., 2008; Taylor et al., 2009)

Which breeds are affected by EIC?

Labrador retrievers

How is the disease inherited?

Each animal has two copies of each gene, one inherited from its mother and one from its father. EIC is an autosomal recessive disease that affects males and females equally.

An autosomal recessive disease implies that two copies of the disease mutation needs to be present in order for the animal to display disease symptoms.

The causative mutation occurs in the DNM1 gene and it entails the substitution of a GTP with a TTP. (Patterson et al., 2008)

Testing for EIC

There is no cure for EIC but the test offered by Inqaba biotec indicates if the dog is clear (homozygous for GTP), a carrier (heterozygous) or affected by the causative mutation (homozygous for TTP).

Clear:Both copies of the gene are normal (homozygous for GTP) therefore the dog will not display the disease symptoms, nor will it pass the mutant copy to its offspring.

Carrier: One copy of the gene is normal and one copy is a mutant copy (heterozygous). These animals will not display the disease symptoms, but may pass the mutant copy to its offspring.

Affected: Both copies of the gene are mutant (homozygous for TTP) and these dogs are very likely to display the disease symptoms. Affected dogs will pass the mutant copy to its offspring.

(Breeders with Labrador Retrievers should test their breeding dogs for EIC. Selective Breeding practices should be practices to prevent this disease. Tests can be done at any age by a mere blood sample. Affected animals should NOT be breed with affected animals or carriers but rather only with clear animals.)